1. Field
This invention relates to kilns, and is directed to a relatively low temperature kiln useful for reactivating carbon.
2. State of the Art
Kilns of various types are in use. Lined kilns are generally operated at very high temperatures to drive moisture, including water of hydration, from substances such as limestone. Activated carbon, after use, is often recycled through an indirect-fired, unlined, rotary kiln for reactivation. Such unlined kilns are of necessity operated at relatively much lower temperatures.
The moving parts of a typical rotary kiln, e.g., the rotating shell, trunnion and thrust roll assembly, drive assembly (consisting of motor, reducer, gears or chain and sprocket), trunnion roll assembly and breeching seals, require servicing, such as lubrication, adjustment of alignment and replacement due to wear or buckling.
Rotary kilns used for the reactivation of carbon are typically about 20 to about 30 inches in diameter and about 20 to about 35 feet in length. Some such kilns are much larger, e.g., 60 inches in diameter and 60 feet long. In any event, they occupy considerable building volume, and provisions for replacement of the rotating shell require the existence of clear space in line with the kiln to allow removal of the shell from its stationary housing.